This disclosure of Japanese Patent Application No. 2001-379448 filed on Dec. 13, 2001 including the specification, drawings and abstract is incorporated herein by reference in its entirety.
1. Field of Invention
The invention relates to an electric motor vehicle, and more particularly to a technique for improving safety of an electric motor vehicle.
2. Description of Related Art
There is a known a system for assuring safety in the event of an accident of an electric motor vehicle which runs on power supplied from a battery like a fuel cell, such as disclosed in Japanese laid-open Patent Publication No. 2001-119815. The system disclosed in this publication is adapted to stop supplying hydrogen to a fuel cell in the event of an accident. Also, Japanese laid-open Patent Publication No. 8-192639 discloses an energy absorbing material and a structure of a battery case which absorb impact energy generated in an accident.
In an electric motor vehicle including a fuel cell, it is necessary to prevent electric shocks to humans due to electric power stored in the fuel cell, and the like, in the event of an accident of the motor vehicle. It is not easy for the related conventional safety systems or methods for an electric motor vehicle to realize protection of energy stored in the battery or safe and reliable consumption thereof in the event of the accident.
It is therefore an object of the invention to provide an electric motor vehicle capable of assuring safe consumption of electric power stored in a battery of an electric motor vehicle in the event of an accident such as a vehicle collision.
According to an embodiment of the invention, an electric motor vehicle is provided with a power source that serves to drive the electric motor vehicle, and a power consuming device that causes electricity generated by the power source to be consumed upon exertion of an impact to the electric motor vehicle owing to a collision of the electric motor vehicle.
Thus, the electric power of the vehicle power source is forcibly consumed in the event of an accident such as a vehicle collision to prevent electric shock to humans after the collision. Also, the structure of the embodiment can be simplified, requiring only one forcible discharging device for one vehicle power source.
In the following description, xe2x80x9can electric motor vehiclexe2x80x9d is not limited, in its definition, to a motor vehicle that uses electric power supplied from the battery as a driving power source, but includes a so-called hybrid vehicle including a motor or motors driven by electric power and a gasoline engine as power sources for driving the motor vehicle.
According to the embodiment, the power source is a battery formed by connecting a plurality of unit cells.
The power consuming device is provided at a position within the electric motor vehicle so as to prevent the power consuming device from being accessed from one of inside and outside of the electric motor vehicle.
The power source includes a fuel cell, the power consuming device has a stack case formed of a resistor for housing the fuel cell. When the fuel cell is brought into contact with the stack case owing to the collision of the electric motor vehicle, electricity generated by the fuel cell is consumed by a resistance of the stack case.
The power source includes a secondary battery, the power consuming device includes an electrical resistance. When the secondary battery is brought into contact with the electrical resistance owing to the collision of the electric motor vehicle, electricity generated by the secondary battery is consumed.
A contact portion at which the fuel cell and the stack case contact is located closer to the fuel cell than a switching device that interrupts connection between the fuel cell and a load connected to the fuel cell in case of the collision of the electric motor vehicle.
A contact portion at which the secondary battery and the electrical resistance contact is located closer to the secondary battery than a switching device that interrupts connection between the secondary battery and a load connected to the secondary battery in case of the collision of the electric motor vehicle.
According to an embodiment of the invention, an electric motor vehicle is provided with a battery that serves as a driving source for generating electric power, a pair of positive and negative electrode portions respectively connected to a positive electrode and a negative electrode of the battery, a resistor formed of a resistive material, and a first and a second contact portions connected to the resistor, the first and the second contact portion facing the positive electrode portion and the negative electrode portion, respectively. The resistor is kept insulated from the battery in a normal operation state of the electric motor vehicle. At least one of the positive electrode, the first contact portion, the negative electrode and the second contact portion are displaced owing to an external force applied to the electric motor in an abnormal operation state such that the electrodes are in contact with their respective contact portions and the positive electrode and the negative electrode are short circuited in an abnormal operation state.
An electric motor vehicle according to a further embodiment includes a battery case that houses the battery, wherein the battery case is formed of a resistor.
The positive electrode portion, negative electrode portion, the first contact portion and the second contact portion are housed in the battery case, and provided in one of a front, a side, and a rear direction of the electric motor vehicle.
The positive electrode portion, negative electrode portion, the first contact portion and the second contact portion is provided on a front portion of the electric motor vehicle.
The battery is formed by stacking a plurality of unit cells. The unit cell is formed of an anode, cathode, and an electrolyte interposed therebetween. Each side of the stacked plurality of unit cells is sandwiched by conductive end plates. The positive electrode portion and the negative electrode portion are connected to the end plates at each side of the positive electrode and the negative electrode.